Someone please God tell me there is a fix for this game. The mouse aim is like a drunken minigame in any other shooter, all over the place and horrid. It's literally unbearable, completely and utterly insane. I don't even know how to describe it... super lag, super unresponsive and then over responsive.
I guess I can play it with a controller if I have to but Christ...
Googling the issue resulted in some rare complaints where people said to turn off v-synch, which I did. It makes it slightly better but still absolutely unplayable. Some people say the Starbreeze engine is always like this but I played Riddick without a problem.
I could be wrong but it suspiciously sounds to me like it could be a mouse acceleration issue. Do you know if there's a way to turn it off, .ini hack or otherwise? (A cursory Google search seems to tell me "no".)
I'm also wondering you could possibly ameliorate this by turning down the dpi settings on your mouse, if you can.
Edit: Might this How-To vid on YouTube help? - http://www.youtube.com/watch?v=JhGP2v_bCpo
Edit 2: The above video just describes how to turn off V-Sync, which you've already tried. I've tried to look for something on how to turn off mouse acceleration but I don't think you can. Is there any chance you could try playing the game with an XBox 360 controller/gamepad?